As compared with traditional wire-based networks, optical-fiber communication networks are capable of transmitting significantly more information at significantly higher speeds. Optical fibers, therefore, are being increasingly employed for communication networks.
To expand total transmission throughput, optical-fiber network providers are attempting to place ever more optical fibers in ever smaller spaces. Packing fibers into tight spaces can cause undesirable attenuation. Indeed, there is an inherent trade-off between increased fiber density and signal attenuation.
Commonly assigned U.S. Pat. No. 6,912,347 (Rossi et al.), which is hereby incorporated by reference in its entirety, achieves optical-fiber cables with high fiber counts and small cable diameters. Such optical-fiber cables are useful for installation into microducts.
Similarly, U.S. Patent Publication No. 2007/0274647 A1 (Pizzorno et al.), now U.S. Pat. No. 7,373,057, each of which is hereby incorporated by reference in its entirety, discloses an optical-fiber cable structure suitable for microduct installation. This publication requires the use of bend-insensitive fibers to reduce cable size.
Many optical-fiber cables designed for installation in microducts (e.g., via blowing) achieve high fiber counts and relatively small cable diameters. Such optical-fiber cables can achieve higher fiber densities, but the constituent buffer tubes have unsatisfactory mid-span storage performance as positioned in pedestals, cabinets, or other optical-fiber enclosures. By way of illustration, after installation in a microduct, an optical-fiber cable typically experiences temperature cycles during use. These temperature cycles can lead to signal attenuation. Thus, a fiber-optic cable that is less susceptible to attenuation is more suitable for such installations (e.g., installations requiring mid-span storage).
Despite efforts to achieve high-fiber-density optical-fiber cables that can be installed in microducts, a need continues to exist for an improved optical-fiber cable that not only possess high fiber count, but also is capable of satisfactory mid-span storage.